If you're looking for a truly authentic local dining experience, you simply can't do better than U Stasi. This tiny, inconspicuous cafeteria tucked in a courtyard (past the pizza place) serves simple home-cooked Polish food at shockingly cheap prices. Being family-owned (80 years and counting) with 'table service' and English and German menus, eliminates it from contention as a true 'milk bar,' but those are about the only differences. Impossible for groups, if you can find a place to sit at all, you'll be doing it in silence at a table of students, pensioners, professors, and homeless people. The plum pierogi are delicious and the experience is simply priceless. Arrive before 14:00 to avoid eating the last thing left on the menu.